feat(iptables): add custom iptables-1.8.11 APKs

This commit should never be merged to master, this is just here as a
temporary change to allow people to test with a version of kube-router
that has a modern iptables userspace.

Hopefully Alpine will carry this package officially in an upcoming
release.

Dockerfile

@@ -37,6 +37,11 @@ RUN apk add --no-cache \
     curl -L -o /usr/local/share/bash-completion/bash-completion \
         https://raw.githubusercontent.com/scop/bash-completion/master/bash_completion
 
+COPY ./build/apks /apks
+
+RUN apk add --allow-untrusted /apks/*.apk && \
+    rm -rf /apks
+
 COPY build/image-assets/bashrc /root/.bashrc
 COPY build/image-assets/profile /root/.profile
 COPY build/image-assets/vimrc /root/.vimrc